A known paver for casting several layers of concrete comprises at least two high compaction concrete paving screeds which are located behind each other, are towed floatingly and are linked by separate towing bars to the chassis. Both paving screeds are situated in operation travelling direction behind the undercarriage. Two hoppers each for one sort of a concrete paving material are provided at the chassis from which hoppers separate longitudinal conveyors extend to the lateral distribution assemblies arranged in front of the respective paving screed. The undercarriage travels on the plane. The first paving screed casts and compacts the lower layer before an upper layer is immediately subsequently cast and compaction thereon. The structure of the paver is relatively complicated. The paver has a large working height. It thus is necessary to install upper paver components such that they can be removed for transport purposes. The weight of the paver is high, in particular in the rear region of the chassis such that in some cases rear cantilevering supporting outriggers equipped with running wheels are needed.
Furthermore, a paver for casting two asphalt layers on top of each other is known from the BAUMA 2004 exhibition (compact asphalt paver) which comprises two high compaction asphalt paving screeds which are linked by separate towing bars to the chassis and operate behind each other and behind the undercarriage. A second removable hopper is provided on top of a hopper which is integrated into the chassis. Separate longitudinal conveyers extend from both hoppers to lateral distribution assemblies in front of the respective paving screeds. The known paver is of complicated construction, very heavy, and has an enormous height. The rear chassis end is additionally supported on the plane by rear cantilevering outriggers equipped with ground wheels.
When casting a fixed trackway, e.g. a railway embankment, with one paver having two floatingly towed high compaction paving screeds of certain working widths e.g. two concrete layers are cast on top of each other each of which may have a thickness up to about 30 cm. This is done e.g. because a single layer of about 60 cm of concrete may be cast but could not be compacted sufficiently in the lower region. The undercarriage travels on the plane. Among other things, the paver is structurally complicated and heavy, because all of the paving material has to be fed longitudinally through the paver and has to be transferred to the towed paving screeds.